In baking, a puff pastry, also referred to as "pâte feuilletée," is a light, flaky, mechanically leavened pastry containing several layers of fat which is in solid state at 20 °C (68 °F). In raw form, puff pastry is a laminated dough composed of two elements: a "dough packet", the détrempe and a "butter packet" or other solid fat, the beurrage. In classic puff pastry, an envelope is formed by placing the beurrage inside the détrempe. In "inverse puff" pastry, an envelope is formed by placing the détrempe inside the beurrage. The resulting paton is repeatedly folded and rolled out.

The gaps that form between the layers left by the fat melting are pushed (leavened) by the water turning into steam during the baking process. Piercing the dough will prevent excessive puffing, and crimping along the sides will prevent the layers from flaking all of the way to the edges.

Puff pastry seems to be a relative of the Middle Eastern phyllo,[1] and is used in a similar manner to create layered pastries. While traditionally ascribed to the French painter and cook Claude Gelée[2] who lived in the 17th century (the story goes that Gelée was making a type of very buttery bread for his sick father, and the process of rolling the butter into the bread dough created a croissant-like finished product), references appear before the 17th century, indicating a history that came originally through Muslim Spain and was converted from thin sheets of dough spread with olive oil to laminated dough with layers of butter, perhaps in Italy or Germany.

The production of puff pastry dough can be time-consuming, because it must be kept at a temperature of approximately 16 °C (60 °F) to keep shortening from becoming runny, and must rest in between folds to allow gluten strands time to link up and thus retain layering.

The number of layers in puff pastry is calculated with the equation:

where is the number of finished layers, the number of folds, and the number of times the dough has been folded. For example, twice-folding (i.e. in three) for four times gives layers. Chef Julia Child recommends 73 layers for regular pâte feuilletée and 729 (i.e. 36) layers for pâte feuilletée fine (in Volume II of her Mastering the Art of French Cooking textbook).[3]

Commercially made puff pastry is available in grocery stores. Common types of fat used include butter, vegetable shortenings, and lard. Butter is the most common type used because it provides a richer taste and superior mouthfeel. Since shortenings and lard have a higher melting point, puff pastry made with either will rise more than pastry made with butter if made correctly; however it will often have a waxy mouthfeel and a blander flavor. Specialized margarine formulated for high plasticity (the ability to spread very thin without breaking apart) is used for industrial production of puff pastry.

Puff pastry is not the same as phyllo (filo) pastry, although puff pastry can be substituted for phyllo in some applications. Phyllo dough is made with flour, water, and fat and is stretched to size rather than rolled. Usually when using phyllo dough, a small amount of oil or melted fat (usually butter) is brushed on one layer of phyllo dough and is topped with another layer. This process can be repeated as many times as desired. When it bakes, it becomes crispy but, since it contains somewhat less water, does not expand to the same degree as puff pastry does.

Nor is puff pastry the same as Austrian strudel dough, or Strudelteig. Strudel dough is more like the phyllo described above.

In addition, since the process of making puff pastry is generally somewhat laborious and quite time-intensive, faster recipes (known as "blitz", "rough puff", or "Flaky pastry"[4]) are fairly common. Many of these recipes combine the butter into the détrempe rather than adding it in the folding process and are thus similar to a folded short crust.